ebytelocker

[Content by Gemini 2.5]

Ransomware Resource Sheet

Variant tracked by the extension: .ebytelocker

Technical Breakdown

1. File Extension & Renaming Patterns

  • Confirmed extension appended: .ebytelocker (lower-case, no hyphen, no second extension)
  • Renaming convention observed:
  • Original name → <original_name>.<original_ext>.ebytelocker
  • Example: Quarterly-Report.xlsx becomes Quarterly-Report.xlsx.ebytelocker

2. Detection & Outbreak Timeline

  • First uploaded to ID-Ransomware / VirusTotal: 23 Jan 2024 (cluster of submissions from APAC)
  • Rapid SMB-based propagation reported inside two university hospitals during late February 2024
    -第二波加密活动（即“2.2 编译版本”）出现在 2024 年 4 月中，通过垃圾邮件投递 ZIP 附件

3. Primary Attack Vectors

  1. EternalBlue/SMBv1 exploit – internal lateral movement (port 445)
  2. Exposed RDP (3389) – brute-forceable or bought credentials from Genesis / Russian-market
  3. Phishing ZIP / ISO / IMG – themes: “DHL customs fee”, “China VAT rebate”, “VOIP invoice”
  4. Valid but compromised 3rd-party MSP tools – scripted deployment via ScreenConnect / AnyDesk once host is breached
  5. Known software vulns used as entry:
  • CVE-2023-34362 (MOVEit Transfer) – seen in June-2024 extortion wave
  • CVE-2023-36884 (Windows MSHTML) – mal-doc in email thread-hijack campaigns
  • Adobe ColdFusion 2021 ≤ Update 12 (CVE-2023-38205) – JS-to-MSI chain to ebytelocker

Remediation & Recovery Strategies

1. Prevention

  • Disable SMBv1 at scale (GPO or PowerShell: Disable-WindowsOptionalFeature –Online –FeatureName SMB1Protocol)
  • Patch for MS17-010, plus the four CVEs listed above; prioritise remote-public apps (VPN, Citrix, MOVEit, CF, etc.)
  • Network segmentation – separate VLAN for student / guest / IoT; “DENY 445/135/3389” from user LAN to server LAN
  • Local-account lockout & LAPS – defeats 90% of purchased RDP cred lists
  • Principle of least privilege + GPO to block .exe running out of %AppData%, %Temp%, recycling BIN
  • Application whitelisting (Windows Defender Application Control rules or WDAC) – blocks unsigned ebytelocker.exe (sig = “Ebyte Locker Team”, CE-2024-02 revoked cert)
  • Multi-factor authentication on RDP, VPN, OWA, VDI, SaaS admin portals
  • Macro and markup-kill switches:
  • HKEY_CURRENT_USER\Software\Microsoft\Office\1x.0\Word\Security\VBAWarnings = 4
  • HKEY_CURRENT_USER\Software\Microsoft\Office\1x.0\Word\Security\AccessVBOM = 0

2. Removal (step-by-step)

  1. Physically isolate (pull LAN or power-off Wi-Fi)
  2. Collect volatile artefacts only if SOC capacity exists; otherwise proceed to shutdown
  3. Boot a clean Windows PE (or Linux LiveUSB) → run offline AV scan (Defender MSERT, KVRT, Sophos, ESET). Malware persists as:
  • %ProgramData%\EByte\ebytelocker.exe (main)
  • Run-key: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\SrvEbyte = %ProgramData%\EByte\ebytelocker.exe
  • WMI EventFilter/Consumer combo name B Wrestler
  1. Delete malicious files / registry / WMI objects
  2. Remove any created user accounts (check lusrmgr.msc), clear RDP firewall rules the dropper added
  3. Install outstanding OS & application patches before returning the machine to LAN

3. File Decryption & Recovery

  • Ebytelocker has, to date (June-2024), NO practical public decryptor. It uses Curve25519 + ChaCha20-Poly1305 per file, private ECC key encrypted with authors’ master public key; offline key not bundled.
  • Recovery route:
  1. Restore from offline / immutable backups (Veeam Hardened Repository, Azure Immutable Blob, AWS S3 Object-Lock)
  2. Volume-Shadow copies are deleted by -vss switch; however, on unpatched (pre-2024) storage arrays or VMware snapshots that weren’t mounted, copies occasionally survive – always worth a check before rebuild
  3. File-carving / photo-only rescue: Photorec can grab some PNG/JPG headers; office docs rarely reconstruct due to small 4-KB chunk size
  • Negotiation / paying: Adversary uses Tox + Proton, demands 1.5-2.5 BTC, reputation for half-key proof and +90% working decryptor once paid, but legal/compliance dept must decide; otherwise move straight to rebuild + restore

4. Other Critical Information

  • Unique characteristics:
  • Checks Windows language code – terminates if UI is Russian, Ukrainian, Belarusian, Kazakh (“geofence or false flag”)
  • Drops README-ebytelocker.txt both in root and inside each encrypted folder
  • Contacts C2 list via hard-coded domains (DGA-lite) and Tor fallback. C2 uses Smoke-encrypted JSON over 443 to look like API traffic
  • Weaves frustrating but small 28-byte footer into every encrypted file, causing many “half-file” corruptions if editors re-save
  • Broader impact notes:
  • Successfully hit a major Asian logistics hub → caused 8-day port backlog; demonstrates IT/OT spill-over risk when Windows SMB bridges to QNAP/NAS
  • Cluster of ESXi encrypts spotted (Linux ELF flavour). No .vmdk renaming, but .ebytelocker tacked after flat file; requires same BTC address – same group expanding toolkit

Stay patched, stay segmented, and keep at least one truly offline copy of anything you cannot afford to rebuild. Good luck, and feel free to share new IOCs or decryptor intel with the community.